Rosvold Continuous Performance Test (CPT)

Background

The Continuous Performance Test (CPT) is a classic neuropsychological assessment of sustained attention created in 1956 by Haldor Rosvold and colleagues at the National Institutes of Health (NIH) as a differential diagnostic for brain damage. The inspiration for the test came from Rosvold's observations of "microsleeps" (brief lapses in attention) in brain-injured soldiers while serving as a psychologist in the Royal Canadian Army during World Ward II. Given the transient nature of these lapses, they were difficult to assess with then-available instruments, so Rosvold designed a custom mechanical apparatus that enabled precise timing of stimulus presentation and response time measurement.

Task Procedure

Rosvold created two versions of the procedure called "X" and "AX", the latter being more difficult.

In the "X" task, participants are shown a series of letters ranging from A to Z, one at a time at an approximate rate of once per 0.92 seconds, and instructed to press a response key if and only if an X appears. For each sequence of 31 letters, a total of 8 Xs are presented. Participants must respond within 0.69 seconds of the onset of an X for the response to be considered correct.

The "AX" task uses the same procedure as the "X" task, except that participants are instructed to press the response key if and only if an X is presented immediately following an A. For each sequence of 31 letters, the AX sequence is presented 6 times.

In both task, the first 62 letters served as practice, with remaining letters used to the score performance. The tasks are run for 10 minutes for adults, and 5 minutes for children.

What it Measures

The CPT is a measure of sustained attention.

Psychological Domains

• Sustained Attention: Ability to maintain focus on a continuous repetitive task over a long time.
• Inhibitory Control: Ability to withold a response to non-target stimuli

Main Performance Metrics

• Omission Errors: Rate of missed targets (inattention)
• Comission Errors: Rate of false alarms, or responses to non-targets (response inhibition)
• Reaction Time: Speed of responses (processing speed, alertness)

Psychiatric Conditions

Performance on the CPT tends to be impaired in patients with the following psychiatric conditions:

• Attention Deficit Hyperactivity Disorder (ADHD)
• Schizophrenia
• Dementia
• Substance Use Disorders